title: Circuit reactivation dynamically regulates synaptic plasticity in neocortex.
abstract: Circuit reactivations involve a stereotyped sequence of neuronal firing and have been behaviourally linked to memory consolidation. Here we use multiphoton imaging and patch-clamp recording, and observe sparse and stereotyped circuit reactivations that correspond to UP states within active neurons. To evaluate the effect of the circuit on synaptic plasticity, we trigger a single spike-timing-dependent plasticity (STDP) pairing once per circuit reactivation. The pairings reliably fall within a particular epoch of the circuit sequence and result in long-term potentiation. During reactivation, the amplitude of plasticity significantly correlates with the preceding 20-25 ms of membrane depolarization rather than the depolarization at the time of pairing. This circuit-dependent plasticity provides a natural constraint on synaptic potentiation, regulating the inherent instability of STDP in an assembly phase-sequence model. Subthreshold voltage during endogenous circuit reactivations provides a critical informative context for plasticity and facilitates the stable consolidation of a spatiotemporal sequence.
authors.affiliation: Committee on Computational Neuroscience, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Kruskal
authors.forename: Lucy
authors.initials: L
authors.lastname: Li
authors.forename: Jason N
authors.initials: JN
authors.lastname: MacLean
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D005260:Female; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology; D008810:Mice, Inbred C57BL; D019579:Neocortex / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D013569:Synapses / Q000502:physiology*; D013788:Thalamus / Q000166:cytology / Q000502:physiology*; D046509:Tissue Culture Techniques